--- title: "Longi Solar LR8-66HYD-650M 650W Solar Panel - Specs & Review | ComparePV" description: "Longi Solar LR8-66HYD-650M 650W solar panel. Specs: 24.10% efficiency, Monocrystalline cells, dimensions, warranty and temperature coefficient." source: "https://comparepv.com/panel/longi-solar-lr8-66hyd-650m" updated: 2026-09-11 --- # Longi Solar LR8-66HYD-650M Middle of its segment, heavy for its output 80 panels in the segment Back Contact 650-700 W ## Identity - **Manufacturer:** Longi Solar - **Model:** LR8-66HYD-650M - **Series:** Hi-MO 9 - **Rated power:** 650 W - **Cell technology:** Back Contact - **Bifacial:** yes ## How it compares Compared against segment Back Contact 650-700 W (80 panels). | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Power (Wp) | 650 W | 660 W | Weak - bottom 10% | | | Module efficiency | 24.10% | 24.40% | Weak - bottom 20% | 219 | | Power density | 240.6 | 244.3 | Weak - bottom 14% | 233 | | Temperature coefficient | -0.260 | -0.260 | Typical | 511 | | Weight (kg) | 33.5 kg | 32.5 kg | Weak - bottom 9% | | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Full peer table | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Module efficiency | 24.10% | 24.40% | Weak - bottom 20% | 219 | | Power density | 240.6 | 244.3 | Weak - bottom 14% | 233 | | Temperature coefficient | -0.260 | -0.260 | Typical | 511 | | Weight per kWp | 51.5 | 49.7 | Weak - bottom 9% | 4,914 | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Watch out for - **51.5 kg per kWp** - Bottom 9% of the Back Contact 650-700 W segment, against a median of 49.7. Ranked 4,914th in the whole database. - **240.6 watts per square metre** - Bottom 14% of the Back Contact 650-700 W segment, against a median of 244.3. - **24.10% module efficiency** - Bottom 20% of the Back Contact 650-700 W segment, against a median of 24.40%. - **Best for:** Residential, utility-scale and hot-climate. - **Not ideal for:** Weight-limited structures, roofs where every square metre has to count and tight roof space. ## Specification ### Electrical - **Rated power (Pmax):** 650 W - **Efficiency:** 24.10 % - **Voltage at Pmax (Vmp):** 41.20 V - **Current at Pmax (Imp):** 15.78 A - **Open-circuit voltage (Voc):** 50.01 V - **Short-circuit current (Isc):** 16.49 A - **Max system voltage:** 1500 V ### Temperature - **Temperature coefficient of Pmax:** -0.260 %/degC - **Temperature coefficient of Voc:** -0.200 %/degC - **Temperature coefficient of Isc:** 0.050 %/degC - **NOCT:** 45 degC ### Cell and construction - **Cell type:** Monocrystalline - **Cell technology:** Back Contact - **Cell count:** 132 - **Bifacial:** yes - **Bifacial gain:** 25.00 ### Physical - **Length:** 2382 mm - **Width:** 1134 mm - **Thickness:** 30 mm - **Weight:** 33.5 kg - **Area:** 2.70 m2 - **Power density:** 240.6 Wp/m2 ### Warranty and degradation - **Product warranty:** 12 years - **Performance warranty:** 30 years - **Output guaranteed at end of warranty:** 88.8 % - **First-year degradation:** 1.00 % - **Annual degradation:** 0.35 % - **Output after 30 years:** 578 W ## Rank in the whole catalogue | Measure | Position | | --- | --- | | Efficiency | 219 of 14005 | | Power density | 233 of 14005 | | Temperature coefficient | 511 of 14005 | | Weight | 4914 of 14005 | | Warranty | 21 of 14005 | ## Pros - **Record 24.8% efficiency via HPBC 2.0** - HPBC 2.0 back-contact cell technology eliminates front-side busbar shading, reaching up to 24.8% efficiency and 670 Wp. That is roughly 3.2 percentage points higher than comparable modules — Hiwatt HW-M12/132H (21.6%) and Techwise Summit Series / Resun RS9H-M (21.57% each) — at the same 670 Wp max power, yielding about 6.4% more installed capacity per equivalent roof area. - **Very low power degradation** - First-year degradation is capped at 1%, with no more than 0.35% annual degradation thereafter, retaining about 88.85% of original power output after 30 years. This clearly outperforms typical PERC modules with annual degradation around 0.5-0.6%. - **30-year linear power warranty** - The manufacturer covers the modules with a 30-year linear power warranty, longer than the industry-standard 25 years offered by most tier-1 manufacturers. Combined with the low degradation rate, this delivers a genuinely higher lifetime energy yield. - **Strong temperature coefficient** - The power temperature coefficient is -0.26%/°C, better than the typical -0.35% to -0.40%/°C for standard silicon modules. This means smaller power losses during summer heat, especially relevant in warmer climates. - **Bankable Tier-1 manufacturer** - LONGi Solar is a BNEF Tier-1 manufacturer, operating since 2000 and among the world's largest PV module suppliers. This bankability status eases project financing for large-scale installations and boosts confidence in warranty servicing. ## Cons - **Shorter product warranty than some peers** - The product warranty is 12 years, while some tier-1 competitors (e.g., other N-type TOPCon modules) offer 15-25 years of product warranty alongside the same 30-year power warranty. This gap is worth noting when comparing servicing terms. - **Back-contact technology price premium** - Back-contact (HPBC) modules typically carry a 5-10% price premium over comparable TOPCon modules due to the more complex cell manufacturing process without front-side busbars. This can raise project LCOE relative to cheaper TOPCon alternatives of similar power class. ## About this series Longi Solar Hi-MO 9 is a breakthrough series of modules that redefines performance standards through the use of advanced **HPBC 2.0 cell** technology. This solution eliminates losses resulting from shading the front part of the cell by busbars, which directly translates into record efficiency and modern aesthetics. These panels are the ideal choice for investors seeking maximum energy yield from limited roof area, effectively solving the problem of space shortages in ambitious projects. Thanks to its optimized internal structure, Hi-MO 9 demonstrates **exceptional resistance to degradation** and stable operation even in low-light conditions, guaranteeing real gains on cloudy days. The innovative design also ensures an **excellent temperature coefficient**, limiting power drops during summer heat. This series is dedicated to both demanding households and large-scale solar farms, where the lowest levelized cost of energy is key. Compared to the competition, Hi-MO 9 stands out with a **unique hybrid structure** that combines the highest efficiency with long-term mechanical reliability. It is a safe and future-proof choice for anyone focusing on the highest quality of workmanship and the most modern technological thought in the photovoltaic industry. ## Notable figures - At 24.1% efficiency, this panel is on par with typical \*\*Back Contact 650-700W\*\* modules - At 240.6 W/m², this panel generates 3.7 W/m² less per unit area than \*\*Back Contact 650-700W\*\* median (244.3 W/m²) - Temperature coefficient of -0.26%/°C matches the \*\*Back Contact 650-700W\*\* median - Weight of 33.5 kg is typical for \*\*Back Contact 650-700W\*\* panels - 70% bifaciality enables rear-side power generation, boosting yield by 4-10% on reflective surfaces ## Questions ### What is HPBC 2.0 technology in the Longi Hi-MO 9 and how does it differ from standard TOPCon cells? HPBC 2.0 is a Back Contact cell technology in which all electrodes are moved to the rear side of the cell. With no busbars shading the front surface, the entire active area captures sunlight. As a result, the Hi-MO 9 achieves a module efficiency of 24.8% and a peak power of 670 Wp, outperforming typical TOPCon modules by approximately 40W in mass production. This translates directly into more energy per square meter of roof space. ### What warranty does the Longi Solar Hi-MO 9 come with and what exactly does it cover? Longi Solar provides a 12-year product warranty covering materials and workmanship, plus a 30-year linear power warranty. After 30 years, the module retains at least 87.4% of its rated power output. Annual degradation is 0.05 percentage points lower than conventional N-type products. As a Tier 1 manufacturer, Longi's financial stability supports the long-term enforceability of warranty claims. ### Does the bifacial design of the Hi-MO 9 offer real benefits on a pitched residential roof? Yes, though the rear-side gain depends on ground albedo and mounting clearance. The Hi-MO 9 achieves a bifaciality factor above 80%, which can add 5–10% extra energy output on light-colored roofing or above a white membrane. For roof-close installations the gain is smaller, but even a 10 cm air gap makes a measurable difference, especially in winter when snow-reflected irradiance can be significant. ### How does the Hi-MO 9 perform in high summer temperatures and in low-light conditions? The Back Contact architecture gives the Hi-MO 9 a temperature coefficient of approximately -0.26%/°C, one of the best figures in the 670 Wp class. Standard PERC modules typically rate at -0.35%/°C. On a hot day with the module at 45°C, the Hi-MO 9 loses roughly 5% less power than a PERC panel. Full-area passivation also improves low-irradiance response, maintaining stable generation on overcast days. ### How many Longi Hi-MO 9 670 Wp panels do I need for a 10 kWp residential system? At 670 Wp per panel, only 15 modules are needed to reach 10.05 kWp. Thanks to the 24.8% efficiency, each panel occupies significantly less roof area than conventional options — a standard 400 Wp module would require 25 panels for the same capacity. Fewer panels also means fewer mechanical and electrical connections, which can reduce installation labor costs. ### Are Longi Hi-MO 9 panels compatible with popular inverters on the market? Yes, the Hi-MO 9 670 Wp operates within the standard voltage and current ranges supported by inverters from Fronius, SMA, Huawei, Growatt, and SolarEdge. The higher short-circuit current (Isc approx. 18–19 A) means the inverter's MPPT input should be rated for at least 20 A. A qualified system designer will configure the correct stringing for Back Contact modules without any compatibility issues. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/Hi-MO-9-V2_LR8-66HYD_625-660M_V30-31374eb45963.pdf) ## Alternatives | Panel | Power | How it differs | | --- | --- | --- | | [AIKO AIKO-A650-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a650-mae72mw) | 650 W | Lighter, +1.1 pp | | [AIKO AIKO-A680-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a680-mde72mw) | 680 W | +30 W, lighter, +1.1 pp | | [AIKO AIKO-A675-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a675-mde72mw) | 675 W | +25 W, lighter, +0.9 pp | | [AIKO AIKO-A645-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a645-mae72mw) | 645 W | Lighter, +0.9 pp | | [AIKO AIKO-A700-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a700-mae78dw) | 700 W | +50 W, heavier, +0.9 pp | | [AIKO AIKO-A695-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a695-mae78dw) | 695 W | +45 W, heavier, +0.8 pp | | [AIKO AIKO-G670-MCH72Mw](https://comparepv.com/panel/aiko-aiko-g670-mch72mw) | 670 W | +20 W, lighter, +0.7 pp | | [Longi Solar LR8-66HGD-595M](https://comparepv.com/panel/longi-lr8-66hgd-595m) | 595 W | -55 W, hotter, -2.1 pp | | [Longi Solar LR7-72HGD-600M](https://comparepv.com/panel/longi-lr7-72hgd-600m) | 600 W | -50 W, hotter, -1.9 pp | | [Longi Solar 600M](https://comparepv.com/panel/longi-600m) | 600 W | -50 W, -1.7 pp, -5 yr warranty | | [Longi Solar LR7-72HTH-605M](https://comparepv.com/panel/longi-lr7-72hth-605m) | 605 W | Lighter, -1.7 pp, -5 yr warranty | | [Longi Solar LR7-72HVHF-670M](https://comparepv.com/panel/longi-lr7-72hvhf-670m) | 670 W | +20 W, lighter, +0.7 pp | | [Jinko Solar JKM650-670N-66QL6-BDV (670W class)](https://comparepv.com/panel/jinko-solar-jkm650-670n-66ql6-bdv-670w-class) | 670 W | +20 W, lighter, +0.7 pp | --- Source: https://comparepv.com/panel/longi-solar-lr8-66hyd-650m Not in this file, on the page: the I-V and temperature curves lifted from the manufacturer's datasheet, a thirty-year output simulator, a bifacial gain calculator and alternatives filtered by how closely they match these dimensions.